The present invention relates to PBX (private branch exchange) interface equipment.
A PBX can be defined as a telephone exchange serving a single organization, having a switchboard and associated equipment, usually located on the customer's premises. The PBX equipment provides for switching calls between any two extensions served by the exchange or between any extension and the national telephone system via a trunk or trunks to a central office. PBX equipment is, of course, well known in the prior art, as numerous manufacturers are providing many types of PBX equipment for virtually every type of business environment.
Typically, the PBX equipment provides connections between a plurality of telephone subscriber lines (extensions) such as those located in a typical office environment and a plurality of trunk lines, typically smaller in number than the subscriber lines. The PBX equipment provides switching functions which permit subscribers, under certain limitations, in an office environment to gain access as required to trunk lines, including WATS (wide area telephone service), DDD (direct distance dialing) and the like, for enabling connections of telephone calls.
As a user's business expands, it frequently becomes desirable to add more features to pre-existing PBX equipment, and to provide expanded capabilities at a reasonable expense. However, a problem in the prior art is that, in order for an installation to provide additional features for the installed PBX equipment, it has been difficult to upgrade the existing PBX equipment because of limitations of space, memory storage, power limitations and the like.
In addition, the general approach with upgrading existing PBX equipment is by connecting additional switching equipment between the existing PBX and the trunks themselves. A further problem with such an approach is excessive costs which necessarily are involved with installations of more expensive switching equipment to the trunk lines.
It would therefore be desirable to provide a system for providing additional capabilities to existing PBX equipment in an office environment while not excessively increasing the cost of such upgrading of the existing equipment.
In view of the above background, it is an objective of the present invention to provide an improved interface equipment for connection to existing PBX equipment.